POMC and NPY mRNA expression during development is increased in rat offspring brain from mothers fed with a high fat diet

Neurodevelopmental Pathways to Obesity and Type 2 Diabetes: Insights From Prenatal Exposure to Maternal Obesity and Gestational Diabetes Mellitus: A Report on Research Supported by Pathway to Stop Diabetes

Incidences of childhood obesity and type 2 diabetes (T2D) are climbing at alarming rates. Evidence points to prenatal exposures to maternal obesity and gestational diabetes mellitus (GDM) as key contributors to these upward trends. Children born to mothers with these conditions face higher risks of obesity and T2D, beyond genetic or shared environmental factors. The underpinnings of this maternal-fetal programming are complex. However, animal studies have shown that such prenatal exposures can lead to changes in brain pathways, particularly in the hypothalamus, leading to obesity and T2D later in life. This article highlights significant findings stemming from research funded by my American Diabetes Association Pathway Accelerator Award and is part of a series of Perspectives that report on research funded by the American Diabetes Association Pathway to Stop Diabetes program. This critical support, received more than a decade ago, paved the way for groundbreaking discoveries, translating the neural programming findings from animal models into human studies and exploring new avenues in maternal-fetal programming. Our BrainChild cohort includes >225 children, one-half of whom were exposed in utero to maternal GDM and one-half born to mothers without GDM. Detailed studies in this cohort, including neuroimaging and metabolic profiling, reveal that early fetal exposure to maternal GDM is linked to alterations in brain regions, including the hypothalamus. These neural changes correlate with increased energy intake and predict greater increases in BMI, indicating that early neural changes may underlie and predict later obesity and T2D, as observed in animal models. Ongoing longitudinal studies in this cohort will provide critical insights toward breaking the vicious cycle of maternal-child obesity and T2D.

ARTICLE HIGHLIGHTS

Neurodevelopmental Programming of Adiposity: Contributions to Obesity Risk

This review analyzes the published evidence regarding maternal factors that influence the developmental programming of long-term adiposity in humans and animals via the central nervous system (CNS). We describe the physiological outcomes of perinatal underfeeding and overfeeding and explore potential mechanisms that may mediate the impact of such exposures on the development of feeding circuits within the CNS-including the influences of metabolic hormones and epigenetic changes. The perinatal environment, reflective of maternal nutritional status, contributes to the programming of offspring adiposity. The in utero and early postnatal periods represent critically sensitive developmental windows during which the hormonal and metabolic milieu affects the maturation of the hypothalamus. Maternal hyperglycemia is associated with increased transfer of glucose to the fetus driving fetal hyperinsulinemia. Elevated fetal insulin causes increased adiposity and consequently higher fetal circulating leptin concentration. Mechanistic studies in animal models indicate important roles of leptin and insulin in central and peripheral programming of adiposity, and suggest that optimal concentrations of these hormones are critical during early life. Additionally, the environmental milieu during development may be conveyed to progeny through epigenetic marks and these can potentially be vertically transmitted to subsequent generations. Thus, nutritional and metabolic/endocrine signals during perinatal development can have lifelong (and possibly multigenerational) impacts on offspring body weight regulation.

Fetal programming of human energy homeostasis brain networks: Issues and considerations

In this paper, we present a transdisciplinary framework and testable hypotheses regarding the process of fetal programming of energy homeostasis brain circuitry. Our model proposes that key aspects of energy homeostasis brain circuitry already are functional by the time of birth (with substantial interindividual variation); that this phenotypic variation at birth is an important determinant of subsequent susceptibility for energy imbalance and childhood obesity risk; and that this brain circuitry exhibits developmental plasticity, in that it is influenced by conditions during intrauterine life, particularly maternal-placental-fetal endocrine, immune/inflammatory, and metabolic processes and their upstream determinants. We review evidence that supports the scientific premise for each element of this formulation, identify future research directions, particularly recent advances that may facilitate a better quantification of the ontogeny of energy homeostasis brain networks, highlight animal and in vitro-based approaches that may better address the determinants of interindividual variation in energy homeostasis brain networks, and discuss the implications of this formulation for the development of strategies targeted towards the primary prevention of childhood obesity.

High-Salt Diet in the Pre- and Postweaning Periods Leads to Amygdala Oxidative Stress and Changes in Locomotion and Anxiety-Like Behaviors of Male Wistar Rats

High-salt (HS) diets have recently been linked to oxidative stress in the brain, a fact that may be a precursor to behavioral changes, such as those involving anxiety-like behavior. However, to the best of our knowledge, no study has evaluated the amygdala redox status after consuming a HS diet in the pre- or postweaning periods. This study aimed to evaluate the amygdala redox status and anxiety-like behaviors in adulthood, after inclusion of HS diet in two periods: preconception, gestation, and lactation (preweaning); and only after weaning (postweaning). Initially, 18 females and 9 male Wistar rats received a standard (n = 9 females and 4 males) or a HS diet (n = 9 females and 5 males) for 120 days. After mating, females continued to receive the aforementioned diets during gestation and lactation. Weaning occurred at 21-day-old Wistar rats and the male offspring were subdivided: control-control (C-C)—offspring of standard diet fed dams who received a standard diet after weaning (n = 9–11), control-HS (C-HS)—offspring of standard diet fed dams who received a HS diet after weaning (n = 9–11), HS-C—offspring of HS diet fed dams who received a standard diet after weaning (n = 9–11), and HS-HS—offspring of HS diet fed dams who received a HS diet after weaning (n = 9–11). At adulthood, the male offspring performed the elevated plus maze and open field tests. At 152-day-old Wistar rats, the offspring were euthanized and the amygdala was removed for redox state analysis. The HS-HS group showed higher locomotion and rearing frequency in the open field test. These results indicate that this group developed hyperactivity. The C-HS group had a higher ratio of entries and time spent in the open arms of the elevated plus maze test in addition to a higher head-dipping frequency. These results suggest less anxiety-like behaviors. In the analysis of the redox state, less activity of antioxidant enzymes and higher levels of the thiobarbituric acid reactive substances (TBARS) in the amygdala were shown in the amygdala of animals that received a high-salt diet regardless of the period (pre- or postweaning). In conclusion, the high-salt diet promoted hyperactivity when administered in the pre- and postweaning periods. In animals that received only in the postweaning period, the addition of salt induced a reduction in anxiety-like behaviors. Also, regardless of the period, salt provided amygdala oxidative stress, which may be linked to the observed behaviors.

FoxO1 Regulates Neuropeptide Y and Pro-opiomelanocortin in the Hypothalamus of Rat Offspring Small for Gestational Age

Adulthood obesity, diabetes, and metabolic diseases are associated with small for gestational age (SGA) newborns. This association could be related to abnormal appetite signaling pathways in the hypothalamus. This study investigated the appetite regulation by the hypothalamus of SGA newborns by establishing an SGA rat model and culturing SGA neural progenitor cells (NPCs) in vitro. Models of SGA were established by maternal food restriction embryonic day 10 (E10). At E18, postpartum day 1 (P1), and P5, hypothalamic neural precursor cells (NPCs) of offspring were cultured in vitro. Immunofluorescence, Western blot (WB), and qRT-PCR were used to assess NPY, POMC, and FoxO1 expression levels. The effects on mRNA expression of the FoxO1-specific inhibitor AS1842856 were examined. The results indicated that compared with controls, NPY was higher, and POMC was lower at embryonic day 18 (E18), postpartum day 1 (P1), and P5. The proliferation and migration of NPCs in the third ventricle of SGA hypothalami were lower than in controls. After treatment with the FoxO1 inhibitor AS1842856, the differences in the mRNA expression of NPY and POMC between the two groups disappeared. NPY and POMC mRNA levels in the SGA group treated with AS1842856 were not significantly different compared with the control group without AS1842856 treatment. In conclusion, SGA pups showed an increase in appetite-promoting NPY and a decrease in appetite-reducing POMC, probably contributing to adulthood weight gain, obesity, and endocrine disorders.

Mechanisms Underlying the Cognitive and Behavioural Effects of Maternal Obesity

The widespread consumption of 'western'-style diets along with sedentary lifestyles has led to a global epidemic of obesity. Epidemiological, clinical and preclinical evidence suggests that maternal obesity, overnutrition and unhealthy dietary patterns programs have lasting adverse effects on the physical and mental health of offspring. We review currently available preclinical and clinical evidence and summarise possible underlying neurobiological mechanisms by which maternal overnutrition may perturb offspring cognitive function, affective state and psychosocial behaviour, with a focus on (1) neuroinflammation; (2) disrupted neuronal circuities and connectivity; and (3) dysregulated brain hormones. We briefly summarise research implicating the gut microbiota in maternal obesity-induced changes to offspring behaviour. In animal models, maternal obesogenic diet consumption disrupts CNS homeostasis in offspring, which is critical for healthy neurodevelopment, by altering hypothalamic and hippocampal development and recruitment of glial cells, which subsequently dysregulates dopaminergic and serotonergic systems. The adverse effects of maternal obesogenic diets are also conferred through changes to hormones including leptin, insulin and oxytocin which interact with these brain regions and neuronal circuits. Furthermore, accumulating evidence suggests that the gut microbiome may directly and indirectly contribute to these maternal diet effects in both human and animal studies. As the specific pathways shaping abnormal behaviour in offspring in the context of maternal obesogenic diet exposure remain unknown, further investigations are needed to address this knowledge gap. Use of animal models permits investigation of changes in neuroinflammation, neurotransmitter activity and hormones across global brain network and sex differences, which could be directly and indirectly modulated by the gut microbiome.

Offspring susceptibility to metabolic alterations due to maternal high-fat diet and the impact of inhaled ozone used as a stressor

The influence of maternal high-fat diet (HFD) on metabolic response to ozone was examined in Long-Evans rat offspring. F0 females were fed control diet (CD; 10%kcal from fat) or HFD (60%kcal from fat) starting at post-natal day (PND) 30. Rats were bred on PND 72. Dietary regimen was maintained until PND 30 when all offspring were switched to CD. On PND 40, F1 offspring (n = 10/group/sex) were exposed to air or 0.8 ppm ozone for 5 h. Serum samples were collected for global metabolomic analysis (n = 8/group/sex). Offspring from HFD dams had increased body fat and weight relative to CD. Metabolomic analysis revealed significant sex-, diet-, and exposure-related changes. Maternal HFD increased free fatty acids and decreased phospholipids (male > female) in air-exposed rats. Microbiome-associated histidine and tyrosine metabolites were increased in both sexes, while 1,5-anhydroglucitol levels decreased in males indicating susceptibility to insulin resistance. Ozone decreased monohydroxy fatty acids and acyl carnitines and increased pyruvate along with TCA cycle intermediates in females (HFD > CD). Ozone increased various amino acids, polyamines, and metabolites of gut microbiota in HFD female offspring indicating gut microbiome alterations. Collectively, these data suggest that maternal HFD increases offspring susceptibility to metabolic alterations in a sex-specific manner when challenged with environmental stressors.

Effects of High-Fat Diet and Exercise Intervention on the Metabolism Regulation of Infant Mice

Maternal exercise is crucial for promoting the health of the offspring. Previous studies showed that long-term maternal exercise improves energy metabolism during pregnancy. Whether swimming exercise can reverse the metabolic disorders caused by high-fat exposure in the early life of the offspring is yet to be elucidated. Three-week-old C57BL/6 female mice were randomly assigned to the standard chow diet group (SC), standard chow diet and exercise group (SC-Ex), high-fat diet group (HFD), and high-fat diet and exercise group (HFD-Ex). After swimming intervention for 13 weeks, male and female mice were caged, and the exercise intervention lasted until delivery. Then, the mothers were fed standard chow diet. A total of 8 offsprings/group were randomly selected after 4 weeks of lactation for GTT and ITT. After body composition analysis, the mice were sacrificed to obtain specimens. The levels of metabolism factors and IL-6 were measured by suspension microarray. Subsequently, 15 min after starting the GTT and ITT, the curve detected significant difference between the HFD and other groups. The body fat percentage of the HFD-Ex offspring was significantly lower than that of HFD offspring (p < 0.05) irrespective of the gender. The levels of IL-6 and TG in the male offspring in the HFD-Ex group were improved significantly (p < 0.05). Compared to the HFD offspring, serum glucose and GIP in the female offspring in the HFD-Ex group was significantly reduced (p < 0.05). Long-term exercise of the mother effectively improved the metabolic disorder caused by high-fat exposure in the infant offspring. Thus, the metabolic inheritance of the offspring is gender-dependent; the maternal metabolism can make male offspring genetically susceptible.

Intermittent fasting, adipokines, insulin sensitivity, and hypothalamic neuropeptides in a dietary overload with high-fat or high-fructose diet in mice

The intermittent fasting (IF) might have benefits on metabolism and food intake. Twelve-week old C57BL/6 J mice were fed a control diet (C, 10% kcal fat), a high-fat diet (HF, 50% kcal fat) or a high-fructose diet (HFru, 50% kcal fructose) for 8 weeks, then half of the animals in each group underwent IF (24 h fed, 24 h fasting) for an additional 4 weeks. Although food intake on the fed day remained the same for all groups, all fasting groups showed a reduction in body mass compared to their counterparts. IF reduced total cholesterol, triacylglycerol, fasting glucose, fasting insulin resistance index, and plasma leptin, but increased plasma adiponectin. IF reduced Leptin gene expression in the HF-IF group, but increased proinflammatory markers in the hypothalamus, also in the C-IF group. Both groups HFru-IF and C-IF, showed alterations in the leptin signaling pathway (Leptin, OBRb, and SOCS3), mainly in the HFru-IF group, suggesting leptin resistance. NPY and POMC neuropeptides labeled the neurons of the hypothalamus by immunofluorescence, corroborating qualitatively other quantitative findings of the study. In conclusion, current results are convincing in demonstrating the IF effect on central regulation of food intake control, as shown by NPY and POMC neuropeptide expressions, resulting in a lower weight gain. Besides, IF improves glycemia, lipid metabolism, and consequently insulin and leptin resistance. However, there is increased expression of inflammatory markers in mouse hypothalamus challenged by the HF and HFru diets, which in the long term may induce adverse effects.

Maternal Obesity during Pregnancy Alters Daily Activity and Feeding Cycles, and Hypothalamic Clock Gene Expression in Adult Male Mouse Offspring

An obesogenic diet adversely affects the endogenous mammalian circadian clock, altering daily activity and metabolism, and resulting in obesity. We investigated whether an obese pregnancy can alter the molecular clock in the offspring hypothalamus, resulting in changes to their activity and feeding rhythms. Female mice were fed a control (C, 7% kcal fat) or high fat diet (HF, 45% kcal fat) before mating and throughout pregnancy. Male offspring were fed the C or HF diet postweaning, resulting in four offspring groups: C/C, C/HF, HF/C, and HF/HF. Daily activity and food intake were monitored, and at 15 weeks of age were killed at six time-points over 24 h. The clock genes Clock, Bmal1, Per2, and Cry2 in the suprachiasmatic nucleus (SCN) and appetite genes Npy and Pomc in the arcuate nucleus (ARC) were measured. Daily activity and feeding cycles in the HF/C, C/HF, and HF/HF offspring were altered, with increased feeding bouts and activity during the day and increased food intake but reduced activity at night. Gene expression patterns and levels of Clock, Bmal1, Per2, and Cry2 in the SCN and Npy and Pomc in the ARC were altered in HF diet-exposed offspring. The altered expression of hypothalamic molecular clock components and appetite genes, together with changes in activity and feeding rhythms, could be contributing to offspring obesity.

Thymoquinone ameliorates obesity-induced metabolic dysfunction, improves reproductive efficiency exhibiting a dose-organ relationship

Women with obesity are more likely to have a complicated reproductive life. Insulin resistance and metabolic dysfunction are associated with obesity. Thymoquinone (TQ) is a well-known antioxidant, considered to be an AMPK-activator. The goal of this work was to investigate the ability of TQ to improve fertility and lactation and clarify the possible mechanism. Female C57BL/6 mice were subjected to High Fat Diet (HFD) supplemented with TQ (10% pmm) and TQ (20% pmm). Histopathological examination was conducted on mammary and ovarian samples. Metabolic and oxidant status was evaluated, and qRT-PCR analysis was performed to verify AMPK/PGC1α/SIRT1 metabolic pathway activity. The present study reports positive effects of TQ on ovarian metabolic function in a dose-dependent manner. TQ showed its positive effects on mammary gland metabolic function at lower dose. This is the first study that indicates these dose related impacts of TQ. Abbreviations: AKT1: serine-threonine protein kinase 1; AMPK: 5' AMP-activated protein kinase; CAT: catalase; CON: control; FBS: fasting blood sugar; GLUT1: glucose transporter 1; GSH: reduced glutathione; GSSG: Glutathione disulfide; HE: hematoxylin and eosin stains; HDL: high-density lipoprotein; HFD: high fat diet; IL-6: interleukin-6; K18: keratin 18; LD: lactation day; LDL: low-density lipoprotein; LKB1: serine-threonine liver kinase B1; MDA: malondialdehyde; mTOR: the mammalian target of rapamycin; NAD: nicotinamide adenine dinucleotide; NADH: nicotinamide adenine dinucleotide phosphate; NS: nigella sativa; PBS: phosphate-buffered saline; PGC1α: peroxisome proliferator-activated receptor gamma coactivator 1-alpha; SIRT1: sirtuin 1; SOD: superoxide dismutase; T-AOC: total antioxidants; TFAM: transcription factor A mitochondrial; TG: triglycerides; TNF-α: tumor necrosis factor-α; TQ: thymoquinone; TQ10: high fat diet + thymoquinone 10% ppm; TQ20: high fat diet + thymoquinone 20% ppm; UCP2: uncoupling Protein 2.